In long term evolution (Long Term Evolution, LTE), a coordinated multi-point transmission (Coordinated Multi-Point, CoMP) technology is introduced, so as to improve a data transmission rate. In a CoMP communication system applying the CoMP technology, a base station side may include a BBU, each BBU may connect to multiple radio remote units (Radio Remote Unit, RRU), and one RRU corresponds to one cell. When joint transmission (Joint Transmission, JT) performance is implemented through the CoMP communication system, the BBU may control multiple RRUs to send, through inter-cell coordination, downlink signals to a same user equipment (User Equipment, UE), so as to improve signal receiving quality of the UE. In the prior art, each RRU corresponds to an antenna array, the RRU has receiving and sending channels, the number of which is consistent with the number of antennas in the antenna array. For example, if an antenna array of a certain RRU includes 2 antennas, two receiving and sending channels are correspondingly set in the RRU. Each receiving and sending channel includes a sending channel and a receiving channel.
In the prior art, in order to ensure channel inequality of an RRU, it is required to correct a channel response of a receiving and sending channel in the RRU, so that a ratio of a channel response of a sending channel of each receiving and sending channel to a channel response of a receiving channel of the receiving and sending channel is the same. However, when downlink signals are transmitted to a UE through inter-RRU coordination, if only a channel response ratio of a receiving and sending channel in each RRU is corrected, a difference may still exist between channel response ratios of receiving and sending channels of different RRUs. Therefore, it is difficult to improve signal quality when signals are sent through inter-cell coordination, thereby reducing the JT performance of the CoMP communication system.